Present Authors Research Articles

Dr John Grant Malcolmson and a reconciliation of the Middle Devonian Lethen Bar and Lethen House fish-bearing nodule localities, with notes on the Middle Devonian nodule beds of the Moray Firth area

The area known as Lethen Bar and Clune, SE of Nairn, Scotland, is a classic Middle Devonian locality, which has yielded nodules or concretions, some of which contain fossil fishes with the highest quality of preservation. The locality was largely centred on farm limestone quarries situated around the perimeter of an isolated outlier of the main fishbed. It was first described in the 19th century, although the upsurge in collecting fossil fishes only occurred some 12 years after the quarries were first mentioned in the scientific literature. Our knowledge of the provenance of the locality is based on very limited accounts, which have never been scientifically tested; these accounts also contain apparent anomalies that have never been adequately addressed. Based on these anomalies, the author of a paper published in 1983 proposed that the locality had been untraceable since the late 19th century and that the outcrop was quarried out. In 2005, the present authors recorded the first scientifically detailed stratigraphical section of the fishbed, followed in 2021–23 by detailed field surveys and by a reappraisal of the literature. This work has resolved the 19th century anomalies and allowed us to confirm the locations of old quarries, to give affirmation to two previously unrecognized sites and to show that the outcrop is still present. Thematic collection: This article is part of the Geology of Scotland collection available at: https://www.lyellcollection.org/topic/collections/geology-of-scotland

Numerical solution of entropy generation in nanofluid flow through a surface with thermal radiation applications

The main purpose of this research is to investigate a mathematical model of nanofluid passing through a stretching sheet having titanium dioxide (TiO2), copper oxide (CuO), and carbon nanotubes (CNTs) as nanoparticles, and sodium alginate is used as a base fluid. The present model can be very useful for numerous fields like Bioengineering, science, and technology. The main reason for using titanium dioxide, copper oxide, and carbon nanotubes nanoparticles as nanomaterials they have many applications in several areas. Moreover, impacts of non-linear thermal radiation and entropy generations are taken into account. By utilizing the similarity transformation technique given system of governing PDEs are transformed into a set of ODE. Then dimensionless equations are numerically tackled via the Keller box method a built-in function in the computer tool MATLAB. To support the present study, physical and numerical interpretations of involved parameters against velocity, temperature, and entropy generation profiles are also presented. From the analysis it is concluded that the combination of a magnetic field and suction reduces the rate of fluid mobility due to the synchronization of the magnetic and electric fields generated by the formation of the Lorentz force. In addition, boosting the thermal radiation parameter raises the present authors' heat transfer rate. The velocity profile drops when the Casson parameter is raised, but the heat and entropy production profiles grow. When the porosity parameter is increased, the velocity profile falls, and the heat and entropy production profiles rise. Additionally the temperature distribution is boosted up with increasing the values of nanoparticles volume fraction. The good agreement between current results and published data is observed. It is necessary to investigate the thermophysical characteristics of the magnetite nanofluid (titanium dioxide, copper oxide, and carbon nanotubes-sodium alginate nanofluid) under various situations. The MHD flow of nanofluid is significant because of its wide range of industrial uses, including flows over the tips of rockets, planes, submarines, and oil tankers. The novelty of this work is to scrutinize the MHD flow and heat transfer analysis of a nanofluid towards a stretched surface. The features of magnetite nanofluid (titanium dioxide, copper oxide, and carbon nanotubes-sodium alginate nanofluid) under entropy generation, thermal radiation and velocity slip are investigated. All of this contributes to the work's uniqueness and novel.

REMARKS ON THE PHYSICAL BASIS FOR THE CONSTRUCTION OF DIFFUSION FLUX TERMS IN FINITE-VOLUME EQUATIONS

The formulation for the diffusion terms in unstructured meshes is compared to that previously derived by the present authors and others for structured body-fitted meshes in terms of direction cosines between the normal and tangential directions. The so-called 'over-relaxed' approach is entirely equivalent/identical, subject to the caveat that the gradient of a scalar field is computed as the product of the scalar and the local surface area vector per unit volume summed (integrated) over the cell volumes, rather than by bilinear field interpolation. The physical/mathematical basis for the 'minimum correction' and 'orthogonal correction' approaches is not consistent with the present authors' derivation, which is in agreement with previous observations. The derivation for a structured mesh here differs from previous work in that physical, rather than mathematical components/projections of vectors are considered, thus filling a significant historical gap in the literature.

Better late (Roman) than never! A possible amphora fragment from 6th century Balatonlelle, Western Hungary

This study reports on a unique finding connected to the re-examination of the ceramic assemblage recovered from the Langobard age (6th century AD) settlement of Balatonlelle, situated in the territory of the former Roman province of Pannonia (now in western Hungary). An undecorated body sherd, not picked up by either the initial typological evaluation of the ceramics or by the preliminary petrographic analysis, was now reassessed by thin section ceramic petrography and scanning electron microscopy. The new analyses revealed that this sherd contains rock and mineral inclusions originated from ophiolites, including slightly serpentinised peridotite fragments. Such rocks do not occur on the surface in Hungary, whereas they are commonly found in the Eastern Mediterranean. The presence of ophiolites in the potsherd indicates that this vessel was produced in a distant territory. The macroscopic characteristics of the sherd combined with its petrographic fingerprint suggest that this pot might have been a transport amphora produced in the Eastern Mediterranean. Although rarely found in Pannonia in the Migration Period, several amphora types, including the most frequently found LRA 1 type, were produced in numerous production centres in the Eastern Mediterranean, in territories geologically congruous with the aplastic inclusions found in the fabric of the Balatonlelle sherd. The significance of this finding is that from Langobard age Pannonia, amphorae occur only sporadically, connected mainly to former Roman settlements. While any conclusions drawn from a single sherd must necessarily remain tentative, this sherd nonetheless provides some material evidence for the existence of some sort of contact between Balatonlelle and the Eastern Mediterranean during the 6th century, be it economic, political or cultural. This study also aims to celebrate the career of György Szakmány, who was one of the key figures to establish ceramic petrographic research and education in Hungary, and trained many generations of petrographers – including the present authors. As such, it also serves as an example how ceramic petrography can bring a new dimension of information to archaeological research.

Activation of the CCL22/CCR4 causing EMT process remodeling under EZH2-mediated epigenetic regulation in cervical carcinoma.

Cervical cancer (CC) is an important public health problem for women, gene expression patterns which were governed by epigenetic modifications can result in CC, CC-chemokine receptor 4 (CCR4) interacts with C-C-motif ligand 22 (CCL22) is associated with tumor progression or metastasis. A previous study by the present authors revealed the levels of chemokine CCL22 and its receptor CCR4 are increased in CC tissues, nevertheless, the regulatory mechanisms governing its expression remain poorly understood. The present study aimed to investigate the potential role of enhancer of zeste homolog 2 (EZH2)-induced epigenetic activation of CCL22/CCR4 and caused epithelial-to-mesenchymal transition (EMT) remodeling in CC. CCL22 and CCR4 were significantly up-regulated in CC samples compared with normal cervix tissues, and obvious induction of promoter DNA methylation levels of CCL22 and CCR4 was found in CC tissues. Demethylation reactivated the transcription of CCL22 and CCR4. DNA methyltransferase 3A (DNMT3A) was found to directly bind to the CCL22 and CCR4 promoter regions in vitro. Downregulation of the expression of EZH2 in CC cell lines altered DNMT3A expression and induced CCL22 and CCR4 promoters' methylation levels, while CCL22 and CCR4 mRNA expression decreased. An in vivo assay showed that EZH2 regulated the expression of CCL22/CCR4 components through DNMT3A, consistent with the in vitro results. In EZH2-silenced CC cells, migration was reduced, levels of EMT-related markers, including vimentin, slug, snail and β-catenin, were all reduced and zona occludens 1 (ZO-1) increased. In DNMT3A-silenced CC cells, migration was induced, vimentin, slug, snail and β-catenin were all induced and ZO-1 was reduced. Inhibition of CCL22 protein significantly decreased migration of CC cells and vimentin, slug, snail and β-catenin levels, while ZO-1 increased. In conclusion, EZH2 appears to regulate CCL22/CCR4 expression via epigenetic activation, causing EMT process remodeling in CC progression.

L’incerto: Paura e bisogno del confine

The concept of border is a much-debated topic, also due to numerous planetary crises of political, economic, and religious origin. The present author supports both the usefulness and the necessity of the border qua psychological entity, insofar as its proper function allows for the process of psychological identification to occur. Moreover, the speed of major socio-cultural changes characterising the contemporary era is argued to be compromising the dynamic psychological balance between growth and transformation, whilst providing the illusion of the psyche as an undifferentiated whole.

Lower Palaeolithic in Korolevo I (Transcarpathia, Ukraine, East-Central Europe): the earliest in Europe?

A recently published article in “Nature” (Garba et al., 2024) claims that lithic finds in the lowermost artefact-bearing sediments of lithological unit 26 at the Korolevo I site (Transcarpathia, Ukraine) are the oldest in Europe, dated to ca. 1.42 Ma with cosmogenic nuclides of gravel pebbles. These surprisingly old dates were then used to build hypotheses on the geochronology and routes of the initial Homo erectus colonization of Europe from the east. The present author reviews all published and unpublished Lower Palaeolithic (LP) data of the Korolevo I site, the field investigations of which he also participated in the 1980s, and came to the following negative results. The dated pebbles in Korolevo I unit 26 are of “intrusive” character, they do not date unit 26 and its lithic finds. Also, the proposed Early Pleistocene interglacial MIS 47, 45 and 43 periods for the LP colonization of Europe either via Asia Minor and the Danube River valley or the Caucasus and the southern part of Eastern Europe do not correspond to the known palaeogeographic and archaeological data from Western Eurasia. Besides, our review of LP contexts in Korolevo I suggests that the so-called lowermost LP lithic artefacts found in situ in archaeological horizon VII within lithological unit 26 in Korolevo I in 1984-1986 are distributed randomly horizontally and vertically. Moreover, they are mostly unworked hyalodacite and siliceous sandstone pieces together with several artefacts redeposited from the sediments above. Accordingly, the only certainly LP material in Korolevo I we know so far is situated in archaeological horizon VI, which is geochronologically associated with the Middle Pleistocene inter-Mindel period or MIS 14, dated to ca. 550 ka BP. However, the Korolevo I site still appears to represent the oldest LP human occupation in both Eastern Central Europe and Ukraine.

(Invited) Understanding Plasma-Assisted Atomic Layer Epitaxy of InN and Opportunities for Collaboration through the Office of Naval Research Global

The family of III-V nitride compound semiconductors has provided the foundation to a number of advanced electronic device technologies from light emitting diodes to radio frequency transistors to power switches. Of the family, binary indium nitride (InN) and ternaries/quaternaries containing InN have progressed at a slower pace due the material properties and related growth challenges. Having the weakest bonds in the family, the material has a lower melting point and more easily decomposes and phase separates (in ternaries and quaternaries). As such, a number of research efforts are looking for new growth approaches to overcome these challenges and realize the InN-based materials that will enable devices such has high speed switches and IR emitters and detectors.To this end, plasma-assisted atomic layer epitaxy (PA-ALE) of InN and InN-containing ternaries has been explored in recent years. Much like atomic layer deposition, ALE consists of a sequence of self-limiting surface half-reactions that promotes “layer-by-layer” growth of films. The cyclical growth process starts with exposure of the growth surface first to the group III precursor (trimethylindium, for example), then purging excess precursor and reaction byproducts leaving only the ad-/physi-/chemi-sorbed species on the surface. After this purge, these surfaces are then exposed to a collection of plasma species (ions, radicals, neutrals, etc.) which reacts with the “sorbed” layer. The growth cycle is finished with a purge of the surface reaction by-products and unreacted plasma species before repeating. The potential of the process is based on the premise that by providing energy from plasma species to the growth surface, one can lower the temperature of growth to improve the stability of the material. Further, the reactive neutral plasma species also play a role by lowering activation energies for chemical reactions compared to thermal ALD, without necessarily providing energy to the growth surface.A brief review of previous experimental demonstrations of epitaxial growth of InN and InN-containing ternaries will be presented showing the promise of the growth method to grow quality InN binary films and metastable ternaries containing InN not possible by conventional growth methods. For example, a metastable cubic phase of InN (NaCl) was realized as were ternary stoichiometries for both InAlN and InGaN that lie in the thermodynamic miscibility gap. Further, and in an effort to begin to understand this growth process and the role that plasma might play in growth mechanisms, synchrotron-based studies have been employed during growth of binary InN and digital InAlN and InGaN alloys. The results of these studies will be highlighted and key findings identified. Most recently, coherent x-ray scattering has been employed to provide additional insights including surface diffusion during each step of the cyclical growth process. The cumulative findings of these efforts will be presented, and future directions outlined.As the presenting author is now detailed as a Science Director for Power & Energy and Advanced Materials to the U.S. Office of Naval Research Global in London, the last portion of the talk will be dedicated to introducing ONRG and its mission to engage international researchers through research grants, travel grants and conference support. The hope is to increase awareness of collaborative opportunities to the global research community expected to be in attendance.

The Enigma of Titanium Electrodeposition on Various Substrates

Titanium is an oxiphilic reactive metal which readily forms passive oxide films onto substrates. The unique properties of the metal such as low density (d=4.5 g/cm3), high strength, and corrosion resistance in harsh environments offers practical advantages. The pure metal is used abundantly in aerospace, armors, submarines, missiles, biomedicals, golf clubs and special electronic applications. The electro-deposition of corrosion resistant coatings is imperative to protect base metals. A review of previous literature has indicated that methods such as roll-diffusion cladding, magnetron discharge sputtering, electron beam, vacuum evaporation, ion beam enhanced deposition (PVD), thermal spray, chemical conversion coatings etc. have been employed in special applications at a prohibitive cost. Plating of titanium films in molten salts at high temperature, and inert atmospheres is a challenge to follow stringent conditions. Electroplating in ionic liquids is extremely expensive and limited.It will be an important technological advancement if a feasible electrodeposition process for titanium is developed for light base metals and plastics in aqueous or semi-aqueous solutions. Titanium electrodeposition in aqueous systems is not a straight-forward process due to its far negative reduction potential than that of hydrogen. Its multivalence states, stability, limited potential range, gas evolution, and substrate passivation pose technical challenges. The present author has critically evaluated several recipes cited by Russian literature, and a few United States patents. Unfortunately, we could not substantiate their cited claims. We have developed an innovative and proprietary process for electro-deposition of Ti in aqueous and partially non-aqueous systems. Deposition of titanium and its alloy films is demonstrated on variety of substrates such as Steel, Pb, Zn, Al, and selected plastics. It is our hope that this endeavor will open new avenues in surface finishing applications.

Transfeminizm(y) – o możliwościach i (granicach) koalicji transfeministycznych

Transfeminist theory makes it possible to think about trans coalitions beyond the alliance formed within the LGB(T) movement. As many authors argue, transfeminism can provide a bridge between feminist and trans politics. However, visions of this coalition vary depending on both their location and the specific author. Since the term “transfeminism” is not widely used in Poland, the purpose of this article is not only to present major transfeminist texts and authors, but also to structure the application of the term and outline its history. The key organizing question of the article, however, is what projects are being formulated within the framework of transfeminist politics and how do they draw a vision of a transfeminist coalition? Since transfeminism is widely considered to be part of third-wave feminism, the article also aims to identify places where transfeminist theory enters into dialogue (and sometimes conflicts) with feminist theory. Key-words: transfeminism, trans studies, feminism, feminist coalitions

გვარის გრამატიკული კატეგორიისათვის მეგრულ-ლაზურში

Verbal voice is topical not only from the Kartvelian but also from a general linguistics viewpoint. It is discussed differently in the European and the Georgian linguistic literature. In Georgian, e.g., voice is considered as a lexical-grammatical (A. Shanidze), morphological (A. Chikobava), syntactic-morphological (B. Jorbenadze) or semantical (D. Melikishvili) category. The issue of establishing systems of opposition in the category of voice is also controversial and topical. Such unresolved problems related to verbal voice require a new understanding of the category and approaches that take into account the specifics of the given research language.In Megrelian-Laz, voice is considered as a grammatical category and according to their morphosyntactic behaviour, two voices are distinguished: The type R-AUX as in avǯiluġi ikips ‘does hunting (= hunts)’ is characteristic only of Laz. It is created as an analogy to Turkish formations (avcılık etmek).The present classification is based on a structured database of verb forms created by the author, which comprises up to 10,000 entries. Directly transitive, indirectly transitive, and intransitive forms of active semantics are grouped together in the database (Laz: o-xvec’-ap-s ‘begs’, Megr: u-per-u-an-s ‘is affectionate to sb/sth’, Zan: ġarġal-ap-s / ragad-an-s ‘speaks’): According to their formation, two types of passives can be distinguished in Megrelian-Laz: independent and conversive.A passive is independent if it is not derived from an active stem via conversion. However, according to the nature of passive, its formation can also be secondary; in particular, in most forms it is based on nominal stems (cf. Zan xomu ‘dried’ > xomu-u-n ‘gets dry’, Laz č’itoni ‘reddish’ > Megr. č’iton-d-u-n ‘gets reddish’). This is why the present author strictly differentiates voice and transitivity. From the category of voice, she separates reflexives of more archaic formation (e.g. i-gurgin-u-n ‘it thunders’, i-rdgabal-u-n ‘talks a lot of rubbish’) which often cause confusion.The typological analysis of Zan verbal forms confirms that, structurally, Megrelian-Laz and Georgian belong to the same type although the formal characteristics of the voice category developed independently in Zan. The patterns can even be different between Megrelian and Laz, but in most cases, content and grammatical form are in complete harmony with each other in Zan. The morphology of Megrelian and Laz is much more regular than that of Svan and Georgian.Despite the high degree of correspondences, grammatical voice cannot be regarded only as a lexical property of a given verb since the verbal voices do not include all realisable forms in Megrelian-Laz. Voice permits the classification of verbs and their division into two categories only according to grammatical (or morphosyntactical) properties.

Study of Interface-Related Mechanisms in the Early Stage Precipitation of σ Phase in Hyper Duplex Stainless Steels

This work aims to computationally explore the diffuse prerequisites for σ phase precipitation in high-alloyed duplex steels. The diffusion control for the early precipitation stage of the σ phase was studied by the Calphad thermodynamic modeling combined with the DICTRA software. Different nucleation sites, α/γ, and α/α and γ/γ grain-boundaries, were studied using thermodynamic and mobility databases developed by the present authors in previous works for high-alloyed duplex stainless steel. Simulation results were compared to experimentally obtained microstructures of aged samples. The study of the concentration profiles of the elements Cr, Mo, and Ni revealed that the precipitation is most favorable within the α phase due to fast mobility and strong thermodynamic driving force favoring the formation of the σ phase. Based on the present results, the role of the different heterogeneous sites for the precipitation of the σ phase in hyper duplex steel is discussed.

The structure maker-structure breaker categories for aqueous electrolytes signify strength of Lewis acidity/basicity relative to water

Small, dissolved ions are commonly categorized as “structure makers” or “structure breakers” based on the implicit assumption that they alter the structure of bulk water. Many authors have questioned the structure maker-structure breaker lexicon, even though the categorization correctly identifies the effects of ions on transport properties. A plethora of studies indicate that the largest impact of ions on water structure occur within one or two water molecules of the ions. The short-range nature of these specific ion effects led the present author to determine if these categories could be defined by ions’ Lewis acidities or basicities relative to water using the bond-valence model. This study found that structure breaking ions are those whose Lewis acidities or basicities were much weaker than water and thus bound water less strongly than water binds to itself. Structure makers are those ions whose Lewis strength was much greater than water’s, leading to stronger binding of water to the ions than water binds to itself. Ions can thus be categorized by their Lewis strength rather than ambiguous structure making or breaking capability.

A study on speciation and enrichment of rare earth elements (REE) by sequential extraction from a potential coal fly ash resource and its role in REE extractability

Coal fly ash (CFA) is a potential secondary Rare Earth Element (REE) source that needs an efficient enrichment and extraction process. Annually, coal-fired power plants generate nearly 1 billion tonnes of coal ash. India alone produced 270.82 million tonnes of CFA in 2021–22. The average global concentration of REE in coal ash is 403.5 mg/kg. The present authors have already studied some promising CFAs from Indian thermal power stations and one such CFA is used in the present study for the sequential extraction (SE), speciation, and enrichment of REEs. Organic acids are used for SE to determine different fractions of REEs and it is found that REEs are mostly associated with amorphous Mn-oxide and organic and sulfide fractions. About 84% of REEs are in the glassy phase that SE cannot dissolve. The main components of CFA and SE residues are quartz, mullite, and glassy phase (52.0–59.2%). The XRF analysis showed that CFA is ‘Class F' (ASTM C618–19). The ESEM – EDS and backscatter imaging revealed monazite-(La) mineral as the REE carrier in CFA. Furthermore, enrichment studies using acid and alkali media have been performed. Alkali treatment with NaOH and KOH increased total REE by 1.61 and 1.32 times, respectively. Acidic treatment with HCl and oxalic acid increased total REE by 1.27 and 1.09 times, respectively. Therefore, NaOH followed by HCl treatment could be a cost-effective and sustainable REE enrichment and extraction method from CFA.

Comment on “Evolution Equations of Nonlinearly Permissible, Coherent Hole Structures Propagating Persistently in Collisionless Plasmas”

AbstractRecent critical remarks, published in this journal, about the present author's analysis of electron and ion holes and their stability are addressed and shown to be misunderstandings and misrepresentations.

Time-Resolved X-ray Absorption Spectroscopy: An MCTDH Quantum Dynamics Protocol.

Expressions for linear and nonlinear spectroscopy simulation in the X-ray window in which the time evolution of a photoexcited molecular system is treated via quantum dynamics are derived. By leveraging on the peculiar properties of core-excited/ionized states, first- and third-order response functions are recast in the limit of time-scale separation between the extremely short core-state lifetime and the (comparably longer) electronic-state transfer and nuclear vibrational motion. This work is a natural extension of Segatta et al. (J. Chem. Theory Comput. 2023, 19, 2075-2091), in which some of the present authors coupled MCTDH quantum dynamics to spectroscopy simulation at different levels of sophistication. Full quantum dynamics and approximate expressions are compared by simulating X-ray transient absorption spectroscopy at the carbon K-edge in the pyrene molecule.

Knowledge and attitudes of Polish prosecutors and general Polish population in regard to post-mortem computed tomography in 2019.

Post-mortem computer tomography (PMCT) is an imaging technique that is gaining popularity both worldwide and in Poland. It provides certain benefits in death investigation that a conventional autopsy is not able to, however, it has significant limitations. As PMCT and post-mortem computed angiography (PMCTA) continue to develop in this country, it is critical to become aware what people know and think about these imaging techniques, especially the prosecutors who officially order such examinations to be performed. In 2019, two concurrent surveys were administered to Polish prosecutors and general Polish population, respectively, regarding their current knowledge and opinions on PMCT. The results were collected both online and on paper, and then subjected to analysis. In total, 92 prosecutors and 227 non-prosecutors responded to the survey. The present authors observed that while prosecutors were more likely to have heard of this examination than the general public, their knowledge was often inadequate or incorrect. Conventional autopsy was still held as the gold standard in death investigation. However, a good popular sentiment towards PMCT was shown, and a desire to learn more about it - not just among prosecutors, but among the general public as well. The present authors' recommendation is that more courses and training should be organised for Polish prosecutors to compensate this knowledge gap.

Essay: Where Can Quantum Geometry Lead Us?

Quantum geometry defines the phase and amplitude distances between quantum states. The phase distance is characterized by the Berry curvature and thus relates to topological phenomena. The significance of the full quantum geometry, including the amplitude distance characterized by the quantum metric, has started to receive attention in the last few years. Various quantum transport and interaction phenomena have been found to be critically influenced by quantum geometry. For example, quantum geometry allows counterintuitive flow of supercurrent in a flat band where single electrons are immobile. In this Essay, I will discuss my view of the important open problems and future applications of this research topic and will try to inspire the reader to come up with further ideas. At its best, quantum geometry can open a new chapter in band theory and lead to breakthroughs as transformative as room-temperature superconductivity. However, first, more experiments directly showing the effect of quantum geometry are needed. We also have to integrate quantum geometry analysis in our most advanced numerical methods. Further, the ramifications of quantum geometry should be studied in a wider range, including electric and electromagnetic responses and interaction phenomena in free- and correlated-electron materials, bosonic systems, optics, and other fields. Part of a series of Essays which concisely present author visions for the future of their field.

Gender diversity at spine surgery academic conferences: a 15-year investigation

Enhancing gender diversity at academic conferences is critical for advancing women's representation and career trajectories in spine surgery. To discover trends in women's representation at major spine conferences over a 15-year period. Conference records from the 2007-2021 annual meetings of the Congress of Neurological Surgeons, North American Spine Society, and Scoliosis Research Society (SRS). Authors of spine-related presentations. Authorship by gender. Retrospective bibliometric analysis with univariate and multivariate modeling to identify trends and predictors of gender diversity. Among 8,948 presentations, 750 (8.4%) had female first authors and 618 (6.9%) had female senior authors. There was no change in rates of female first authorship (p=.41) or senior authorship (p=.88) over time. The strongest predictors of female first authorship were having a female senior author (OR 7.32, p<.001), and delivering presentations at SRS (OR 1.95, p=.001). Factors negatively associated with female first authorship included poster format (OR 0.82, p=.039) and conference location in the United States/Canada (OR 0.76, p=.045). Similar trends were encountered for senior authorship. Productivity per senior author was similar between genders (p=.160); whereas a gender gap in productivity per first author during 2007 to 2011 (p=.020) equalized by 2017 to 2021 (p=.300). Among the 10 most productive authors of each gender, male authors delivered more presentations, but all authors shared similar format, content, and location. Women's representation in spine-related presentations did not increase at three major conferences over a 15-year period. Our findings regarding the positive effects of female mentorship, and international or virtual venues merit further investigation to address the gender gap. The upstream pipeline of recruiting women into academic spine surgery also needs to be addressed.

Reappraisal of stratigraphic position of a sandstone included in the Bagh Formation, exposed near Belam Bujurg, Khargone District, Madhya Pradesh, India

A sandstone included in the Bagh Formation occurs at Belam Bujurg, District Khargone, Madhya Pradesh. Its stratigraphic position is controversial. Bose considered it as Nimar Sandstone. His observation, that it is capped by a limestone containing bryozoans, implies that Sitapuri Bryozoan Limestone directly overlies Nimar Sandstone at Belam Bujurg. However, it is contradictory to Chiplonkar’s (1982) observation that Nodular limestone is invariably associated with Nimar Sandstone. According to Roy Chowdhury and Sastri (1954, 1958), this sandstone is an intercalation within the Sitapuri Bryozoan Limestone. Later, Badve (1987) correlated this sandstone with Nimar Sandstone on the basis of similar ichnofauna and believed that overlying limestone cap represented calcareous facies coming at the top of Nimar Sandstone. However, elsewhere frequency and variety of trace fossils are distinctly more in limestone layers, in comparison to sandstone layers. Moreover, the presence of similar trace fossils indicates similarity in the conditions of deposition, rather than correlation. Recent fieldwork by the present authors corroborates that this sandstone is an intercalation within Sitapuri Bryozoan Limestone. Identification of the bryozoan Limestone was confirmed by petrographic study in thin section.